Absorption refrigeration



April 21, 1953 I w. G. KGEL 2,635,436

ABsoRPTIoN REFRIGERATION Filed April 21,' 1947 3 sheets-sheet 1 April 21, 1953 w: G. KGEL ABsoRPTIoN REFRIGERATION Filed April 21, 1947 5 Sheets-Sheet 2 April 21, 1953 w. G. KGEL 2,635,436

ABSORPTION REFRIGERATION Filed April 21, 1947 3 Sheets-Sheet 3 x /ll 7' gvm Patentecl Apr. 21, 1953 ABSORPTION REFRIGERATION Wilhelm Georg Kgel, Stockholm, Sweden, as-

signor to Aktiebolaget Elektrolux, Stockholm;

Sweden, a corporation of Sweden Application April 21, 1947,!se1-ia1N0. 7423180 V' In Sweden May 4, 1946 This invention relates to refrigeration and is especially concerned With refrigerators of the absorption type.

The objects of this invention are to provide an absorption type refrigerator of improved appearance and utility; to provide in such a refrigerator a new arrangement for circulating refrigerant fluid; to provide a new cooling or evaporator structure for producing refrigeration at a plurality of temperatures; and to provide a new relation of such evaporator structure with other parts for effectively creating several compartments in a refrigerator cabinet with better distribution of the evaporator structure and other elements of the refrigerator.

The invention in one phase is concerned with distributing refrigerating effect of a plurality of evaporator or cooling elements operable at different temperatures. For effectively utilizing the storage space of a refrigerator cabinet, the cooling elements are embodied in a partition Which serves to subdividev the storage space into a plurality of compartments. The partition is formed in such a manner that the individual refrigerating or cooling effects produced by the cooling elements are predominantly made available to effect cooling of separate compartments at opposite sides of the partition.

In laccordanc'e With the invention, this is accomplished by providing a partition in the form of a container having spaced apart walls. The evaporator or cooling elements, which may be formed of piping,I for example, are in thermal exchange relation with the inner surfaces of oppos'ing walls of the container. The walls are spaced apart a sufiicient distance to provide a gap between the cooling elements, and the container is filled with insulating material for thermally shielding the cooling elements from one another. The partition may be horizontally disposed in a storage space of a refrigerator cabinet to subdivide the space into a plurality of compartments one above another and between which circulation of air is substantially prevented. In such case, the upper wall of the containeriforms a supporting shelf for an upper compartment de- -fined by the walls of the storage space and the partition.

' In an absorption type refrigeration system employing inert gas or auxiliary agent, the different elements or parts are permanently Secured together to provide a hermetically closed system. To assemble the refrigeration system and a re- .frigerator cabinet and locate' the cooling element in a thermally insulated space of the cabinet,

14 vClaims. (Cl. 62-99) 2 a removable wall section' or closure member is provided at an opening in one of the cabinet walls; When the refrigeration system and cabinet are 'assembled 'and the wall opening is closed by the removable wall section, parts of the system project through the wall section with the cooling element disposed within the storage space of the cabinet. V i

When the partition of the invention is provided for a plurality of cooling elements of an absorption refrigeration system of the inert gas type,,the partition may be formed as a unitary part of the refrigeration system before the latter is assembled with thev cabinet. A horizontally disposed partition may be of such dimensions that, upon being inserted into the interior of the cabinet through the wall opening, it will extend from one lateral side Wall to'the opposite lateral side wall of the storage space and fromV the rear wall to the'front access opening, so as to subdivide the space into-upper and lower compartments between which-circulation of air is substantially prevented. By employing a container as a partition within which the cooling elements are disposed, the coolingl structure itself is utilized to advantage to create several compartments in the storage space of the cabinet. Further, the container serves as a closed housing for' the cooling elements which are located in the storage space, thereby providing a refrigerator of improved appearance' and utility. I V 'In another phase of the'invention, the container for the cooling element of an absorption type refrigeration system forms a unitary structure with the removable wall section to enclose and house the conduits connected to the cooling element and parts of the refrigeration system disp'osed outside the interior of the cabinet. In efiect, this new arrangement provides an apparatus space for a number of parts of the refrigerator in which one portion of the unitary housing structure is Within the interior of the cabinet and another portion thereof is in the plane of the wall formed with the opening and adapted to close the latter. Such unitary housing structure may be advantageously employed to house many parts of an absorption refrigeration system of the inert gas type, such as the gas heat exchanger and'connections therefrom -to the cooling element, thereby providing a relation of'parts in which the opportunity for moisture to penetrate into the insulation of the refrigerator cabinet is minimized.

. The invention is also concerned with a new araeaacse rangement for supplying liquid refrigerant to a plurality of cooling elements of an absorption refrigeration system of the inert gas type, whereby the average or mean temperature of one cooling element is lowered and the mean temperature differential between such cooling element and another cooling element is increased. This is accomplished by flowing inert gas successively through first and second cooling elements, and flowing liquid refrigerant withdrawn from the first cooling element in heat exchange relation with liquid refrigerant flowing to such cooling element before the withdrawn Vliquid refrigerant is conducted to the second cooling element. The heat transfer between liquid refrigerant fiowing to and fromacooling element, while out of the presence of inert gas, may be accomplished by a suitable liquid heat exchanger. Such heat exohanger may also be located in'the unitary housing structure and embedded in insulation with vother parts of the refrigeration system.

The invention, together :with the above and other objects and advantages thereofJ -will be more fully understood upon reference to the following description and accompanying -drawings forming a part of this specification, and of which:

Fig. 1 illustrates more or less diagrammatically an .absorption refrigeration system yof the .inert gas type embodying the invention;

Fig. .2 is a 'front velevation of .a plurality of cool ing elements and connections thereto diagrammatlcally illustratlng one practical 'form of carrylng out the inventlon shown in Fig. 1;

Fig. 3 is a top plan view of the cooling elements and connections thereto shown in Fig. 2;

Fig. 4 is a fragmentary view diagrammatically illustrating another manner in which the liquid refrigerant connections to the cooling elements in Figs. 2 and 3 may be eifected;

Fig. 5 is a front elevation of-a plurality of cooling elements and connections thereto illustrating another practical form of carrying out the invention shown in Fig. 1;

Fig. 6 isa top plan view of the cooling elements and connections thereto shown in Fig. 5;

Fig. 7 isa fragmentary vertical sectional view of a refrigerator .provided with a horizontal partition which subdivides the storage space into a plurality of compartments and in which the'cooling-elements of Figs. S and :6 are embodied;

Fig. 8 is a fragmentary :sectional view ofthe horizontal partition and-refrigerator .cabinet taken at the line 8-8 of Fig.-'7-; .and

Fig. 9 is a fragmentary lvertical isectional view, similar to Fig.'7, illustrating in side elevation the unitary housing structure which includes the horizontal partition and portion adapted fto close the opening in the cabinet wall and in which parts of the refrigeration system connected to .the cooling elements are enclosed.

Referring to Fig. l, the invention is emboclied in an absorption refrigeration system of a uniform pressure type in which'an inert gas or auxiliary pressure equalizing agent is employed. .In .a system of this type a refrigerant fluid, such as liquid ammonia, for example, is introduced .through a conduit H into the evaporator or cooling structure l2. The refrigerant fluid evaporates and diffusesin cooling structure [2 into an inert gas, such as hydrogen, for example, tov pro- .duce a refrigerating effect. The resulting gas mixture of refrigerant and inert gas flows from the cooling structure through an outer passage -M of a gas heat exchanger l5 and vertical'conduit IS into an absorber comprising a vessel ll and a looped coil lt.

In the absorber vessel I 'I and coil IB refrigerant vapor is absorbed by a suitable absorbent, such as water, for example, which is introduced into coil [8 through a conduit l9. The hydrogen or inert gas, which is practically insoluble and 'weak in refrigerant, is returned to the cooling structure lZ through an inner passage 20 of the gas heat exchanger [5 and a conduit Zl. From the vessel ll enriched absorption liquid flows through a conduit 22 and an inner passage 23 of a liquid heat exchanger into the lower end of a vapor lift tube 24 of a generator unit 25.

'The generator unit 25 comprises a heating flue 26 having the vapor lift tube 24 and a boiler pipe '21 in .thermal exchange relation therewith, as by welding, for example. By heating generator unit 25, as by a gas burner 28, for example, liquid from the inner passage 23 of the liquid heat exclianger is raised by vapor lift action through tube 24 into the upper part of the boiler pipe 21. The liberated refrigerant vapor entering boilet pipe 21 through the tube 24, and also vapor expelled from solution in theboiler pipe, flows upwardly into an air-cooled condenser-29 provided with a. plurality of .cooling fins 30. Refrigerant vapor .is liquefied in the condenser 29 and returned to the cooling structure |2 .through Vthe conduit ll to complete the refrigerating cycle.

The lower end of the condenser 29 is connected by conduit 3l to the gas circuit, as to the upper part of absorber coil I8, for example,.so that any non-condensable gas which .may pass into the condenser can flow to the gas circuit .andinot be trapped in the condenser. The weakened absorption liquid, from which Vrefrigerant vaporhas been expelled, is conducted .from boiler Pipe 21 through a conduit 32, outer ypassage V33 of the liquid heat exchanger, and conduit |9 into the upper part of the absorber col [8.

The cooling structure IZ comprises two cooling elements |2a and .l2b which are shownin-the form of coils and adapted to be positioned in the thermally insulated interior of a refrigerator cabinet. The cooling element |2a may be suitably arranged in a storage space to provide one or more freezing compartments adapted to receive trays for freezing .water and other matter to be frozen. The cooling element |2b is'arranged with a plurality of cooling heat transfer ns 34 whereby a relatively extensive surface is provided for cooling air in a storage space.

The cooling elements I2a and |2b are connected in series relation with inert gas from conduit 2| flowing upwardly through cooling element Ita in the presence of and in counterflow to liquid refrigerant which is introduced through conduit ll. From the upper part of cooling element l2a inert gas then passes through conduit 35 for downward fiow through the lower cooling element l2b. Unevaporated liquid refrigerant is conducted from the lower part of cooling element |2a through a conduit 36 communicating with the conduit 35. Liquid refrigerant introduced into conduit 35 flows downwardly in cooling element |2b in the presence of and in parallel flow with the inert gas.

Since the inert gas flows successively through the coolings elements |2a and l2b, the gas in the upper cooling element I 2a contains a lesser amount of refrigerant vapor than the gas in the lower cooling element IZb. The partial vapor pressure of the refrigerant is a gradient, so that the temperature of liquid refrigerant in the cooling elements is also a gradient, the evaporating temperature of liquid being lower in the upper cooling element |2a which constitutes the freezing portion of the cooling structure.

In accordance with this invention, a liquid heat exchanger 31 is provided in the circuit for circulating liquid refrigerant, whereby liquid withdrawn from Cooling element I2a flows in heat exchange relation with liquid flowing toward cooling element |2a before the withdrawn liquid is introduced into cooling element l2b. With this arrangement heat is transferred from liquid refrigerant prior to entering cooling element l2a to the cool liquid leaving the cooling element, thereby lowering the temperature of the liquid entering the cooling element l2a. By Cooling the liquid refrigerant in this manner before it enters the cooling element l2a, the mean or average temperature of the upper cooling element is lowcred, thereby improving the operation of this portion of the cooling structure for freezing water and the like.

Due to liquid heat exchanger 31, liquid is introduced into the lower cooling element l2b at a higher temperature than it would if entering directly from the upper cooling element l2a. With this arrangement, therefore, the mean or average temperature of the lower cooling element is increased. Thus, by reducing the mean temperature of the freezing portion of the cooling structure |2 and raising the mean temperature of the space cooling portion thereof, a wide temperature differential of the mean temperatures of the two portions is efected.

In Fig. l the conduit il is formed to provide a liquid trap for sealing the condenser 29 from cooling element I2a. Likewise, the conduit 36 is formed to provide a liquid trap into which liquid overflows from a receiver or reservoir 38 provided at the lower end of cooling element l2a.. The liquid heat exchanger 31 is formed by securing the conduits ll and 35 in thermal exchange relation, as by welding, for example, at regions thereof forming parts of the liquid traps and normally filled with liquid. Since the conduits I and 36 are in thermal exchange relation along their lengths for a considerable distance and the liquid in these conduits is in counterflow, heat of liquid is eifectively abstracted from liquid in conduit II and given up to liquid in conduit 36.

The temperature at which liquid evaporates and diffuses in the gas mixture in cooling element l2a, at the gas outlet end thereof, is dependent upon the partial pressure of refrigerant vapor in the gas mixture. Since the temperature of the liquid refrigerant introduced into cooling element l2a is higher than the temperature at which evapcration of liquid takes place, heat is absorbed from the liquid with evaporation thereof to bring down its temperature.

By precooling the liquid introduced into cooling element l2a, less of the refrigerating effect is utilized to bring down the temperature of the liquid and a lower mean or average temperature is maintained in cooling element l2a. By increasing the temperature of the cooling liquid passing from cooling element IZa before such liquid is introduced into lower cooling element l'2b, refrigerating effect in the latter is utilized to absorb heat from the liquid, after passing through the liquid heat exchanger 3'1, Whereby the mean or average temperature in cooling element |2b is increased.

I, 'I'he evaporator or cooling structure l2 in Fig.

1,togetherxwiththe arrangement for circulating 6 liquid refrigerant in the manner just described, lends itself to a horizontally disposed cooling structure in which the latter extends over substantially the entire width of a space to be cooled.

Such a practical embodiment of the invention is shown in Figs. 2 and 3 in which par-ts similar to those shown in Fig. 1 are designated by the same reference numerals. A vertically disposed gas heat exchanger IS' is shown in Figs. 2 and 3 instead of the horizontally disposed gas heat ex'- changer |5 illustrated in Fig. 1. It is to be understood that the vertical gas heat exchanger I 5' will be connected in an absorption refrigeration system in a manner generally like that shown in Fig. 1 and described above.

The cooling structure l2' in Figs. 2 and 3 comprises horizontally disposed cooling elements l2a and i2b in the form of looped coils each of which is positioned in a single substantially horizontal plane and adapted to extend from one lateral side to the opposite lateral side of the storage space of a refrigerator cabinet. Inert gas weak in refrigerant flows from the upper end of the absorber coil IB through an inner passage 20' of the gas heat exchanger 15' and a conduit 39 into the receiver 38' provided at one end of the upper looped lcoil forming cooling element I2a. The inert gas flows through the straight sections 40 and connecting bends 4| of the cooling element |2a to the enlarged liquid inlet end 42 thereof.

Liquid refrigerant from the condenser is conducted through conduit ll' to the enlarged end 42 of the upper cooling element l2a. The straight sections 40 of the upper looped coil are arranged to be parallel to the lateral side walls of the storage space of the cabinet in which it is to be inserted, the straight sections 40 being at such elevations that liquid refrigerant will flow by gravity through cooling element lZa from the upper liquid inlet end 42 thereof to the lower receiver end 38' thereof in counterflow to the inert gas.

Inert gas passes from the upp-er liquid inlet end 42 of the cooling element |2a through the vertical conduit connection 35' which is connected at its lower end at 43 with one end of the lower looped coil forming cooling element l2b. Liquid refrigerant collecting in the receiver 38' at the lower end of the upper cooling element |2a is conducted i therefrom through conduit 136' to an intermediate lby gravity from the vertical conduit 35' toward the lower end 45 of the lower looped coil. The straight sections 44 of the lower looped coil are transverse to the straight sections 40 of the upperv looped coil and may be arranged with cooling finsv 34' to provide a relatively extensive surface 'for cooling air. Such cooling fins 34' are shown only in Fig. 3 in order to simplify :the drawings,

The resulting gas mixture of refrigerant vaporand inert gas flows from the lower cooling element l2b at 45 through a conduit 46, outer passuitable horizontally disposedpartition may bel aesaese arranged'between the cooling elements |2a and lzb, so that cooling element |2a may be effectively employed for freezing water and the like in one subdivided compartment and cooling element |2b may be employed for cooling air in another compartment. If desired, a suitable metallicplate or shelf may be arranged in thermal exchange relation with the looped coil forming the upper cooling element |2a for supporting ice trays and other matter to be frozen. The gas heat exchanger l' may be embedded in insulation and arranged exteriorly of the thermally insulated storage space, as in a vertical space usually provided at the rear of the Cabinet, for example.

As shown in Figs. 2 .and 3, the .conduit H' through Which liquid refrigerant is conducted from the condenser 29 to the upper cooling element |2a includes a portion Ha which extends crosswise of the cooling structure 12' between the receiver 38' and enlarged liquid inlet end 42. Likewise, conduit 36' through Which liquid refrigerant is conducted from the lower end of cooling element |2a to the upper end of cooling element .I2b extends across the cooling structure l2' alongside the portion Ha of conduit The conduits I l' and 36' are in thermal exchange relation for a considerable distance in a lengthwise direction, as by welding, for example, to form the liquid heat exchanger 31' Which corresponds to the liquid heat exchanger 31 illustrated in Fig. 1 and described above. Conduits Il' and 36' are each formed to provide a liquid trap, as best seen in Fig. 2, so that the portions of these conduits in thermal exchange relation are normally filled with liquid for effectively transferring heat from liquid being conducted to cooling element I 2a to liquid passing from such cooling element and about to enter cooling element l2b..

By virtue of the horizontal disposition of the cooling structure IZ' in Figs. 2 and 3, a liquid heat exchanger 31' of considerable length is provided to lower the average or mean temperature of the upper cooling element |2a and increase the average or mean temperature differential between the cooling elements. With this arrangement it is not necessary to extend and position the liquid refrigerant circulation conduits any great distance from the cooling structure, thereby permitting the liquid heat exchanger to be arrange'" closely adjacent to and at substantially the same elevation as the cooling structure l2'.

Heat transfer is effected between conduits II' and 36' with liquid in parallel flow through these conduits, as indicated by the arrows in Fig. 3. The liquid heat exchanger may assume a variety of forms and the liquid in one conduit may be in counter-flow to the liquid in the other conduit. As shown in Fig. 4, for example, a portion of conduit 36' may be surrounded and enveloped by a jacket 41 to provide a liquid heat exchanger 31a having an outer passage l lb connected in the conduit ll' through which liquid refrigerant is conducted from the condenser 29 to the upper cooling element l2a of the cooling structure. Further, the outer passage Hb of the liquid heat exchanger 31a may be connected in the refrigerant supply line in such a manner that liquid is conducted through conduit 36' in counterflow to liquid in the outer passage Hb, as indicated by the arrows in Fig. 4.

Figs. 5 and 6 illustrate another practical embodiment of the cooling structure |2 of Fig. l in which a horizontally disposed gas heat exchanger 15 is located practically at the same elevation as the 'cooling structure 12" and closely adjacent to a liquid heat exchanger 31" like that shown in Figs. 2 and 3 and just described. As will be described hereinafter, inert gas weak in refrigerant flows from the upper end of the looped absorber coil |8 into a jacket 48 formed at one end of the gas heat exchanger I5" which is transverse to the main longitudinal axis thereof.

The jacket 48 surrounds one end of the gas heat exchanger, Whereby inert gas weak in refrigerant flows from the interior of jacket 48 through the inner passage 20 and a short vertical conduit connection 39' into the enlarged lower end 38" of the looped coil forming the upper cooling element |2a of cooling structure |2". The inert gas flows through the upper looped coil in counterflow to liquid refrigerant which is conducted through conduit II" to the enlarged upper end 42' of the coil.

The upper cooling element |2a in Figs. 5 and 6 is similar to the corresponding upper cooling element in Figs. 3 and 4 in that it is disposed in a single substantially horizontal plane and the straight sections 40' thereof are arranged to be parallel to the lateral side walls of a cabinet space in which it is adapted to be located. The inert gas passes from the upper cooling element |2a through the vertical conduit connection 35 to the looped coil forming the lower cooling element l2b. Liquid refrigerant collecting in the receiver 38 at the lower end of upper cooling element |2a flows through conduit 36 to the vertical conduit connection 35" for parallel flow with the inert gas in the lower cooling element.

The looped coil forming the lower cooling element l2b in Figs. 5 and 6 is like the upper cooling element in that the straight sections 44' of this looped coil are parallel to the straight sections 40' of the upper looped coil. The elevations of the straight sections 40' and straight sections 44' of the two looped coils are such that liquid refrigerant will flow by gravity from the enlarged end 42' to the receiver 38 in the upper coil and from the conduit connection 35" to the point 49 in the lower coil at which region the latter communicates with the outer passage I 4" of the gas heat exchanger 15" at an end thereof.

The resulting gas mixture of refrigerant vapor and inert gas formed in the cooling structure |2", which passes therefrom at the point 49 of the lower coil, flows through the outer passage I4" of the gas heat exchanger to the absorber in a path of flow which will be described presently.

The liquid refrigerant conduits I l" and 36" in Figs. 5 and 6 extend across the cooling structure l2" in the same manner as the corresponding conduits Il' and 36' in Figs. 2 and 3 to provide the liquid heat exchanger 31. Conduits ll" and 36" are formed to provide liquid traps, as best shown in Fig. 5, whereby heat transfer is eifected at the liquid heat exchanger 31" in portions of the conduits normally filled with liquid.

The embodiment in Figs. 5 and 6 possesses all of the advantages of the previously described embodiment illustrated in Figs. 2 and 3, and, in addition, provides a relation of the cooling structure l2", gas heat exchanger l5", and liquid heat exchanger 31" in Which all of these parts are practically at the same elevation, thereby enabling these parts to be arranged relatively close to one another and at the same time providing for a circuit for circulating liquid refrigerant which is of distinct advantage, especially for producing refrigeration at a plu'fality of different temperatures.

- The arrangement and relation of refrigerator .parts illustrated in Figs. and 6 may be employed to advantage by locating the upper and lower cooling Velements |2a and l2b above and below .va horizontal partition, respectively, Which is provided in any suitable manner in a thermally insulated space of a household refrigerator. In such case the lower cooling element desirably -may be provided with cooling fins like the cooling fins 34' shown in Fig. 3.

In further accord4 with the invention, however, the upper and lower cooling elements l2a and l2b of Figs. 5 and 6 may be embodied in a partition which serves to subdivide the thermally insulated storage space of a household refriger- -ator into a plurality of compartments. an arrangement is illustrated in Figs. 7, Band 9 Such in Which parts similar to those shown in Figs. 5 and 6 are designated by the same reference numerals.

The refrigerator in Figs. '1 and 8 comprises a Cabinet 59 having an inner liner or metal shell 5| arranged to be supported within an outer metal shell 52 and insulated therefrom with any suitable insulating material 53. The inner metal shell defines a thermally insulated storage space 54 into which access is afforded by a door 55 hinged to the front of the cabinet. A horzontally disposed partition 55 is provided in the storage space 54 to subdivide the space into upper and lower compartments 51 and 58, respectively.

The partition 56 comprises a box-like container 56 which is formed of suitable sheet metal and extends substantially over the entire width and depth of the space 54, whereby circulation of air between the upper and lower compartments 51 and 58 to all practical purposes is substantially prevented. If desired, suitable rails 66 may be provided at the lateral side walls of the inner liner 5| for supporting the container 59.

The cooling vstructure l2" of Figs. 5 and 6 is embodied in the container 59 in such a manner that the cooling effect produced by one of the cooling elements is predominantly made available to effect cooling of one of the compartments at one side of the partition 56, and the cooling effect produced by the other of the cooling elements is predominantly made available to effect cooling of the other compartment at the opposite side of the partition.

In the illustrated embodiment this is accomplished by arranging the looped coils forming the cooling elements I2a and l2b in thermal exchange relation with the inner surfaces of the opposing horizontal walls of the container 59. Asv shown, the looped coil forming the upper cooling element l2a is in thermal exchange relation with the bottom surface of the top horizontal wall of the container 59, and the looped coil forming the lower cooling element l2b is in thermal exchange relation with the top lsurface of the bottom horizontal wall of the container.

The container 59 is of such depth that a gap is formed between the cooling elements l2a and l2b when these parts are in thermal exchange relation with opposing walls of the container. The container 59 is filled with suitable insulating material Bl for thermally shielding the cooling elements from one another. Thus, cooling elements |2a and l2b form a part of the partition 56 which embodies heat transfer structure whereby the cooling effect produced by each cooling element is predominantly made available at the wall of the container 59 with which each cooling element is in heat exchange relation.

The cooling or refrigerating effect produced by the higher located cooling element l2a, Which is the lower temperature section of the cooling structure l2, is effectively utilized to effect cooling of the upper compartment 51 which is defined by the partition 56 and the thermally insulated walls of the refrigerator Cabinet 50. Hence, the upper compartment may be referred to as a freezing space adapted to receive ice trays, frozen food packages and other matter to be frozen. The freezing compartment or section 51 may be provided with a hinged door 62 at the forward edge of the partition 56 which may be spring-biased to its closed position and provided with a suitable handle to facilitate the opening thereof. The hinged door 62 may desirably be formed of glass or other suitable transparent material. The top horizontal wall of the container 59, at the underside of which the looped coil forming upper cooling element I2a is disposed, is substantially flat and can be eifectively employed as a supporting shelf for the upper freezing compartment 51.

The cooling effect produced by the lower located cooling element l2b, which is the higher temperature section of the cooling structure 12. is eifectively utilized to cool air in the lower com- (partment 58. By providing the arrangement described above for circulating liquid refrigerant and locating the cooling elements in a sheet metal container 59 in which the cooling elements are thermally shielded from each other by an insulating material like glass wool, for example, an outer temperature differential on an average of about l0 C. has been obtained when the room temperature is as high as 43 C.

As shown in Fig. 8, the outside straight sections 40' and 44' of the looped coils forming the upper and lower cooling elements |2a and I2b, respectively, are spaced from the vertical side Walls of the partition 56. Also, the front connecting bends of the looped coils are spaced from the front vertical wall of the partition, as seen in Fig. 7. Thus, the top and bottom walls of the container 59 form the chief or primary heat absorbing surfaces for the upper and lower subdivided compartments 51 and 58, respectively.

Since the outside straight coil sections and front connecting bends of the loopedcoils are thermally shielded from the side and front vertical walls of the container 59, the sheet metal vertical walls provide the only metallic heat conducting path between the top and bottom heat absorbing surfaces of the container. The heat conductive path formed by the front and side vertical container walls is sufiiciently small so that a temperature differential is maintained between the top and bottom walls of the container which will insure maximum thermal efficiency of the cooling structure. Even when the container 59 is snugly fitted in the thermally'insulated space 54 of the cabinet and the vertical side walls thereof contact the lateral sidewalls of the inner liner 5l, the contact between the inner liner and the side vertical walls of the container 59 provides a poor heat conductive path which is insufficient to impair the temperature differential maintained between the top and bottom walls of the container. For hygienic and other reasons a snug fitting of the container 59 within the storage space 54 is preferable, especially to prevent water and the like penetrating therebetween. i

In providing the partition of the invention, the container 59, which is desirably formed of sheet metal, is positioned over the looped coils forming the coolng elements |2a and I2b, so that the latter are in contact with the inner surfaces of opposing walls of the container. The container and looped coils therein may then be dipped into a body of molten zinc or other suitable corrosion protecting agent. In this way all parts are effectively protected against corrosion. and at the same time a good heat conducting Path between the coils and container walls is provided by the zinc which possesses good heat conducting properties. It is to be understood tha-t other materials Which resist corrosion, such as stainless steel and chrome-plated copper, may be used equally well.

The top horizontal wall of the container 59-is desirably smooth so that a good heat conducting path is provided for abstracting heat from ice trays and the like which are placed upon such top wall. The bottom horizontal wall provides a relatively extensive heat transfer surface for abstracting heat from air passing over the partition 56. At the bottom horizontal wall of the container 59 heat transfer fins may be provided, if desired, to increase the heat transfer surface for coolng air in the lower compartment 58.

In order to position the coolng structure l2 within the thermally insulated space 54, the rear wall of the cabinet is formed with an opening 63 Which is substantially as wide as the storage space 54. In accord with the invention, a unitary structure 64 is provided which not only includes the container 59 for the cooling structure but also a housing 65 Which serves as a cover or closure for the opening 63 and houses parts of the refrigerator.

The housing 65 comprises a rectangular frame 66 formed of suitable insulating material, such as wood, for example. The container 59'at the rear thereof is formed with outwardly extending flanges 6-1 which are-fixed to the inner side of the frame 66. To the outer side of the frame 66 is fixed a cover plate 68-Which is of greater area than the opening 63 so that the peripheral edgesthereof will bear against the-outer shell 52;

The opening 63 in the rear wall of the cabinet is defined by a rectangular frame structure 69 which also may be formed of Wood, for-example. It willbe noted that the edgesfl'l of the inner liner l, at the vicinity of the opening 69, project beyond the inner peripheral edges of the frame structure 69 to provide an abutment in the path of movement of the housing 65 when the latter is positioned in the opening 63. A gasket 'H of suitable insulating material is provided between the edge portions 10 of the inner liner Si and'the flanges 61 of the container 59 to form an airtight seal about the opening formed in the inner liner.

Further, the gasket 'Il and Wooden frame 66 of the housing 65 provide aL poor 'heat'conducting path at the rear end of the container walls to promote the desired distribution of coolng effect at the top and bottom walls of the container 59. When the container 59 is positioned in the storage space 54, gasket 'H is firmly held in place by removably securing the outer cover plate 68 to the outer shell 52, as indicated at 12.

The unitary structure 64, which includes the container 59 and housing 65, provides an apparatus space which is eifectively utilized to enclose the coolng elements |2a and l2b, the gas heat vexchanger l5", and liquid heat exchanger 31 illustrated in Figs. 5 and. 6. The gas heat exchanger I5" is arranged in a lengthwise position within the housing 65 and is disposed in the plane of the rear Wall of the cabinet 58 when the housing 65 is in position at the rear wall of the cabinet. The liquid heat exchanger 31 is positioned alongside of the gas heat exchanger l5" and both of these parts, as well as thegas and liquid refrigerant connections to the coolng elements l2a and IZb, are embedded in insulation 13.

By embedding the refrigerator parts in insulation in the housing 65, condensation of moisture on the parts is eifectively prevented. It will be seen that the jacket 48 at one end of the gas heat exchanger l5'I projects through an opening in the outer cover plate 68 into the space at the rear of the cabinet 50 in which other parts of the refrigerator, such as the condenser and absorber, for example, are located to promote air coolng of these parts.

The jacket 48 envelops and surrounds an end of the gas heat exchanger l5" which projects rearwardly from the housing 65. The rich mixture of the refrigerant vapor and inert gas formed in coolng structure l2" flows through the outer passage l4" of the gas heat exchanger and a conduit |6' which is adapted to be connected at its lower end to the absorber vessel in a manner similar to the conduit |6 in Fig. 1. The upper end of an absorber coil, like the coil |8 in Fig. 1, is arranged to be connected to a conduit Ha which is disposed about the conduit IG' and communicates at its upper end with the jacket 49. Hence, in the embodiment of Figs. 5 and 6 which is incorporated in the household refrigerator cabinet illustrated in Fig. 7, inert gas weak in refrigerant flows upwardly through conduit |8a into the interior of jacket 48 which surrounds and envelops the end portion of the outer passage I4" through which relatively cool gas flows to the absorber.

Since Warm gas flows into the interior of jacket 48 in its path of flow from the absorber to the coolng structure |2", atmospheric air is prevented from contacting an exposed part of the refrigerator which is suificiently cold for moisture in the surrounding air to condense on the outer surfaces thereof. Inasmuch as the inner surfaces of jacket 48 are contacted by Warm gas, no condensate forms on the outer surfaces thereof Which are exposed to atmospheric air.

It will now be understood that the housingr 68 and container 59 provide a unitary structure which serves as an apparatus space in Which the coolng elements and other parts of the refrigerator are completely closed off with respect to the thermally insulated storage space 54. In this way, a refrigerator of improved appearance and utility is provided which is easily kept clean and sanitary. Further, an arrangement and relation of the cooling structure and parts connected thereto is made possible which is especially useful for producing refrigeration at a plurality of temperatures.

While several embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that various modifications and changes may be made without departing from the spirit and scope of the invention, as pointed out in the following claims.

What is claimed is:

1. A refrigerator comprising a cabinet having thermally insulated walls forming a space, an

absorption refrigeration system employing an inert auxiliary gas which includes a cooling element in the space, a gas heat exchanger for gas flowing to and returning from said cooling element and a liquid heat exchanger for liquid refrigerant supplied to and passing from said cooling element, structure providing a chamber for housing said cooling element and gas and liquid heat exchangers, said housing containing insulation in Which said gas and liquid heat exchangers are embedded, and said cooling element being in thermal exchange relation with an inner wall surface of said housing.

2. A refrigerator comprising a Cabinet having thermally insulated walls forming a space, an absorption refrigeration system employing an inertr auxiliary gas which includes a cooling element, a gas heat exchanger for gas flowing to and returning from said cooling element and a liquid heat exchanger for liquid refrigerant supplied to and passing from said cooling element, and structure providing a chamber for housing said cooling element and gas and liquid heat exchangers, one part of said structure serving as a removable section for one of said Walls from Which another portion housing said cooling element projects inwardly into said space.

3. For use with a household .refrigerator cabinet having Walls defining a thermally insulated interior, an absorption type refrigeration system including superimposed first and second cooling elements in which refrigerant evaporates in the presence of an auxiliary agent, each of said cooling elements comprising piping including straight sections and connecting bends in a single substantially horizontal plane which is adapted to extend between the lateral side walls of the interior of the cabinet, the refrigerant evaporating into the auxiliary agent at a low temperature in said first cooling element and at a higher temperature in said second cooling element, a first conduit through which refrigerant is conducted to said first cooling element, a second conduit for withdrawing lliquid refrigerant from said first cooling element out of the presence of the auxiliary agent and conducting such refrigerant to said second cooling element, said first and second conduits having horizontally extending portions Which are in thermal exchange relation at an elevation substantially at the vicinity of said cooling elements.

4. The combination set forth in claim 3 including a horizontally disposed container having spaced apart top and bottom walls for housing said cooling elements, said first cooling element being in thermal exchange relation With the underside of the top wall and said second cooling element being in thermal exchange relation with the top surface of the bottom Wall.

5. A refrigerator including a cabinet, an absorption type refrigeration system having first and second cooling elements in which refrigerant evaporates in the presence of an auxiliary agent, said cooling elements effecting cooling of thermally segregated spaces in the cabinet, said refrigerant evaporating into auxiliary agent at a low temperature in said first cooling element and at a higher temperature in said second cooling element, means including a first conduit for supplying refrigerant to said first cooling element, means including a second conduit for supplying refrigerant to said second cooling element from said first cooling element, said first and second conduits being in heat exchange relation.

6. A refrigerator including an absorption refrigeration system employing an inert-auxiliary gas having a cooling element in which refrigerant fiuid evaporates in the presence of such gas, a heat exchanger having first and second passages for refrigerant fiuid flowing to and from said element, respectively, said second passage through which refrigerant fiuid flows. from said element having an ascending portion formed to hold a body of such fiuid in a liquid state before overflowing therefrom, a cabinet having thermally insulated walls, one of saidrwalls having an opening closed by a removable insulated section for inserting the cooling element into the cabinet, said heat exchanger being disposed within and embedded in said removable insulated wall section.

7. A refrigerator including a cabinet having thermally insulated walls, an absorption refrigeration system having first and second cooling elements through which an inert auxiliary gas flows in series and in which liquid refrigerant evaporates in the presence of such gas, a gas heat exchanger for gas fiowing to said first cooling element and gas flowing from said second cooling element, a liquid heat exchanger for liquid refrigerant flowing to said first cooling element and liquid refrigerant passing from the latter to said second cooling element, one of said Walls having a removable insulated section for inserting said cooling elements into the cabinet to effect cooling of thermally segregated spaces therein, said gas and liquid heat exchangers being embedded in said insulated Wall section.

k8. A refrigerator as set forth in claim 7. in which said gas and liquid heat exchangers are horizontally disposed Within said removable wall section alongside one another.

9. In the art of refrigeration with the aid of an absorption refrigeration system having first and second cooling elements in which refrigerant fiuid evaporates in the presence of an inert gas, the improvement which comprises supplying refrigerant fiuid to said first evaporator and from said first evaporator to said second evaporator, flowing inert gas through said first evaporator and th'ence through said second evaporator, lowering the mean temperature of said first evaporator by abstracting heat of liquid from refrigerant fiuid supplied thereto prior to' entering such evaporator, and raising the mean temperature of said second evaporator by utilizing the abstracted heat to heat refrigerant fiuid passing from said first evaporator to said second evaporator.

10. In the art of refrigeration with the aid of an absorption refrigeration system having first and second cooling elements constructed and arranged for liquid cooling agent to fiow successively therethrough by gravity and in which such refrigerant fiuid evaporates in the presence of an inert gas, the improvement which comprises flowing inert gas successively through said first and second cooling elements, supplying to said first cooling element all of the liquid cooling agent normally made available in the system for said cooling elements, and exchangingheat between the liquid cooling agent supplied to said first cooling element and the liquid cooling agent passing from said first cooling element and flowing to said second cooling element.

11. In the art of refrigeration with the aid of an absorption refrigeration system including an inert gas circuit having a place of evaporation in Which liquid refrigerant evaporates in the presence of an inert gas, the improvement which gasa-:se

comprlses-expelllng refrigerant vapor from solution at a'place ofheating, condensing such refrigerant vapor at a place of condensation, supplying liquid refrigerant from-the place of condensation to said place of evaporation in a first path of flow having a liquid-trap, conducting liquid refrigerant from said place. of evaporation at a point removed from the region to which liquid refrigerant isA supplied thereto and in a second path of flow having a liquid trap, and exchanging heat between liquid refrigerant in said first and second paths of flow atv regions thereof. normally filled-with liquid.

12. In the art of refrigeration with the aid of an absorption refrigeration system having first and second Coolingelements in which liquid refrigerant evaporates in the-presence of an inert gas. theimprovement which comprises supplying liquid refrigerant to said first Cooling element for flow therein and flowing liquid from said first cooling element in heat exchange relation with liquid supplied to said first cooling element and then to said second cooling element for flowtherein.

13. A refrigerator comprising a cabinet including thermally insulated walls defining a space having a front access opening and closure means therefor, such walls including top, bottom, rear and lateral side walls, an-absorption refrigeration-system of the inert gas type including a plurality of cooling elements operable at different average temperatures, meansincluding a horizontal member to subdivide said space into separate compartments, said horizontal member defining a bottom portion of one compartment and a top portion of another compartment and comprising a container'which includes spaced apart upper and lower horizontally extending walls and connecting vertical walls at the front and sides thereof, one of said cooling elements being in good heat conductive connection with the underside of the upper horizontally extending wall of said container and the other cooling element beingin good heat conductive connection with the top surface of the lower horizontally extending' wall of said container, said upper horizontally extending wall constituting a shelf to support matter adapted to be refrigerated.

14. A refrigerator comprising a thermally lnsulated cabine providing a space, having a front access opening and closure means therefor, said Cabinet including an inner liner having a top, bottom and vertically extending rear and side walls, one of said vertically extending walls having a normally closed opening, a refrigeration system comprising a plurality of interconnected parts including a low temperature cooling element and a higher temperature cooling element, means including a horizontal member which is inser-table into and removable from the space through said liner wall opening and divides the space into a plurality of compartments between which circulation of air is substantially prevented, said horizontal member comprising a container having spaced apart upper and lower walls, and said low temperature Cooling element being in thermal relation with the underside of said upper wall and said higher temperature cooling element being in thermal exchange relation With the upper side of said lower wall, the separation of said low and higher temperature cooling elements within the interior of said container being markedly small and inadequate to provide useful storage space for food preservation and freezing purposes in the normal use of the refrigerator.

WILHELM GEORG KGEL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date l,533,646 Givens Apr. 14, 1925 1,949,651 Maiuri Mar. 6, 1934 2,l35,875 Morse Nov. 8, 1938 2,16%,537' Pierce Aug. 8, 1939 2,239',583 Schmieding Apr. 22, 1941 2,242,282 Bergholm May 20, 1941 2,260,939 Hainsworth Oct. 28', 1941 2,261,682 Hedlund Nov. 4, 1941 2,26l,683 Kuenzli Nov. 4, 1941 2,289,0'78l Schellens et al July 7, 1942 2,345,453' Brace Mar. 28, 1944 2,345,505 Si'edle Mar. 28, 1944 

